Overflow system for bathtub or other receptacle

ABSTRACT

An overflow system is described for a water receptacle ( 22 ) such as bathtub, sink or washbasin having a water tap for connection to a water supply. The system includes sensing means, such as a float ( 14 ), for sensing an overflow condition of the receptacle, and a supply valve ( 65 ) responsive to the sensing means and arranged to close the water supply to the tap. The supply valve may be hydraulically controllable via a control port ( 68 ) thereof. A control valve ( 59 ) is provided between the water supply and the control port The control valve is responsive to the sensing means so that upon such an overflow condition it open and the pressure of the water supply is applied to close the supply valve. Thus, there is no need for a supply of electricity.

[0001] This invention relates to an overflow system for a waterreceptacle such as a bathtub, sink or washbasin.

[0002] Conventionally, bathtubs, for example, are provided with anoverflow outlet at a level near the top of the bathtub, the overflowoutlet being connected to the waste pipe leading from the bathtub.Accordingly, once the level of water reaches the overflow outlet, theexcess water can drain away to reduce the risk that water will spillover the upper edge of the bathtub and cause a mess and possible damage.Nevertheless, in some cases the overflow cannot cope with the rate offlow required to prevent spillage, for example if the pressure of thewater supply to the taps is very high, or if the overflow passageway hasbecome partly or completely blocked. Furthermore, preventing a bathtubfrom overflowing by draining away the excess water is wasteful of water.

[0003] There have been various proposals to deal with these problems.For example, systems are known for automatically opening the normal plugof the bathtub when the water level reaches a predetermined level, butsuch systems still result in wasted water. Also, electrical systems areknown for automatically turning off the supply of water to the bathtubwhen the water level reaches a predetermined level, but such systemsrequire a supply of electricity and a great amount of care in design andinstallation to prevent any risk of electrical shock. Furthermore,mechanical systems are known for automatically turning off the supply ofwater to the bathtub when the water level reaches a predetermined level,but such systems suffer variously from the problems of: bulkiness (e.g.WO99/11876); that they would be difficult to reset when applied to abathtub (e.g. GB2312838); that reliance is made purely on the buoyancyof a float to provide the motive force to close off the water supplyvalve(s) (e.g. GB2288330); or that they need to be reset by a mechanismthat it may be difficult to make accessible in a bathroom scenario (e.g.WO93/09303).

[0004] Simply stated, a first aspect of the invention provides anoverflow system that uses the pressure of the water supply to close offthe water supply when the bath (or other receptacle) overflows. Thus,there is no need for a supply of electricity, and reliance is not madepurely on the buoyancy of a float to provide the motive force to closeoff the water supply.

[0005] Alternatively stated, the first aspect of the invention providesan overflow system for a water receptacle such as a bathtub, sink orwashbasin for connection to a water supply, the system including sensingmeans for sensing an overflow condition of the receptacle, and a supplyvalve responsive to the sensing means and arranged to close the watersupply, characterised in that the supply valve is hydraulicallycontrollable via a control port thereof, a control valve is providedbetween the water supply and the control port, and the control valve isresponsive to the sensing means so that upon such an overflow conditionthe control valve opens and the pressure of the water supply is appliedto the control port of the supply valve to close the supply valve.

[0006] (As used above, the phrase “close the water supply” is notintended to imply that the water supply is completely closed off.)

[0007] Preferably, the supply valve comprises a plunger movable betweena closed position in which a first end of the plunger closes the watersupply and an open position in which the first end of the plunger opensthe water supply, the second end of the plunger being exposed to thepressure applied to the control port. In this case, the cross-sectionalarea of the first end of the plunger exposed to the pressure of thewater supply is preferably less than the cross-sectional area of thesecond end of the plunger exposed to the pressure applied to the controlport, so as to provide a form of hydraulic amplification.

[0008] In the case where the system is for use with such a waterreceptacle connected to a second water supply (e.g. hot-water supply),preferably the system further includes a second supply valve arranged toclose the second water supply, the second supply valve beinghydraulically controllable via a control port thereof (which may beshared in common with the first supply valve), the control valve alsobeing provided between the first-mentioned water supply and the controlport of the second supply valve so that upon opening of the controlvalve the pressure of the first water supply is applied to the controlport of the second supply valve to close the second supply valve. Insome cases, the pressure of the cold-water supply is greater than thepressure of the hot-water supply, and in these circumstances it ispreferably the cold-water supply that feeds the control valve.

[0009] In the case where the system is for use with such a receptaclehaving a (conventional) overflow outlet, preferably the system furtherincludes: an actuating element for operating the control valve, theactuating element being held in a first position before such an overflowcondition and moving from the first position to a second position uponsuch an overflow condition; and a manually-operable resetting elementfor moving the actuating element back from the second position to thefirst position, the resetting element projecting through or beingaccessible through the overflow outlet. Accordingly, there is no need tomake an additional hole in the wall of the bathtub, or to make a hole inthe bath surround, in order to provide access to the resetting element.

[0010] Preferably, the system further comprises a detent element forholding the actuating element in the first position, and the sensingmeans comprises a float for floating on water that has escaped throughthe overflow outlet and arranged to release the detent element uponrising of the float.

[0011] The resetting feature mentioned above may also be applied toother forms of overflow system, such as the electrically-powered orfloat-powered systems acknowledged above, with similar advantages.Accordingly, a second aspect of the invention provides an overflowsystem for a water receptacle such as a bathtub, sink or washbasinhaving an overflow outlet and being for connection to a water supply,the system including sensing means for sensing an overflow condition ofthe receptacle, and being changeable in response to such an overflowcondition from a first state in which the supply is open and a secondstate in which the supply is closed, and the system further including amanually-operable resetting element for changing the system back fromthe second state to the first state, characterised in that the resettingelement projects through or is accessible through the overflow outlet.Again, there is no need to make an additional hole in the wall of thebathtub, or to make a hole in the bath surround, in order to provideaccess to the resetting element.

[0012] In the first or second aspect of the invention, the effectiveheight of the overflow outlet relative to the receptacle may beadjustable. Therefore, the overflow outlet can be set to the level towhich it is desired to fill the receptacle and the water supply/ies canbe opened. Then, once the water level reaches the set level, the watersupply/ies will automatically close. The receptacle can therefore beleft unattended to fill to the desired level without any significantwaste of water.

[0013] This latter feature may also be applied to other forms ofoverflow cutoff system, such as the electrically-powered orfloat-powered systems acknowledged above, with similar advantages.Accordingly, a third aspect of the invention provides an overflow systemfor a water receptacle such as a bathtub, sink or washbasin having anoverflow outlet and for connection to a water supply, the systemincluding sensing means for sensing an overflow condition of thereceptacle in which water flows into the overflow outlet, and means forclosing the water supply in response to such an overflow condition,characterised in that the effective height of the overflow outletrelative to the receptacle is adjustable.

[0014] In one embodiment, the height of an entrance into the overflowoutlet is adjustable, and in another embodiment, the height of anoverflow passageway leading from the entrance into the overflow outletis adjustable.

[0015] A fourth aspect of the invention provides a water receptacle,such as a bathtub, sink or washbasin, having an overflow systemaccording to the first, second and/or third aspect of the invention.

[0016] Specific embodiments of the present invention will now bedescribed, purely by way of example, with reference to the accompanyingdrawings, in which:

[0017]FIG. 1 is a front view of a plumbing unit;

[0018]FIG. 2 is a rear view of the plumbing unit;

[0019]FIG. 3 is a sectioned side view, taken along the section line A-Bshown in FIGS. 1 and 2, of the plumbing unit in a first state;

[0020]FIG. 4 is a sectioned side view, taken along the section lineA-C-D-E shown in FIGS. 1 and 2, of the plumbing unit in a stateintermediate its first and second states;

[0021]FIG. 5 is similar to FIG. 4, but with the plumbing unit in itssecond state;

[0022]FIG. 6 is a sectioned plan view, taken along the section line F-Fin FIG. 3, of the plumbing unit;

[0023]FIG. 7 is a sectioned plan view, taken along the section line G-Gin FIG. 3, of the plumbing unit in its first state;

[0024]FIG. 8 is similar to FIG. 7, but with the plumbing unit in itssecond state;

[0025]FIG. 9 is similar to FIG. 3, but showing a modified plumbing unit;

[0026]FIG. 10 is a schematic sectioned side view of the tap end of abathtub having another modified plumbing unit;

[0027]FIG. 11 is a view of the end of the bath in the direction 11marked in FIG. 10;

[0028]FIG. 12 is similar to FIG. 10 but showing a further modification;and

[0029]FIG. 13 is a view of the end of the bath in the direction 13marked in FIG. 12.

[0030] Referring to the FIGS. 1 to 8 of the drawings, the plumbing unithas a housing 10 which, for simplicity, is shown in the drawings as asingle element, but which in practice would be built up from a number ofcomponents assembled together. The upper end of the housing 10 providesa float chamber 12 containing a vertically movable toroidal float 14. Ashort pipe 16 projects from the front wall 18 of the float chamber 12,near the upper end of the float chamber 12, and passes through anoverflow hole 20 in the wall 22 of a bathtub. The housing 10 is held inplace by a perforated rosette 24 that is attached to the pipe 16 byscrews 26. Accordingly, when the water in the bathtub reaches theoverflow level, it can pass through the rosette 24 and the pipe 16 intothe float chamber 12 causing the level of the float 14 to rise.

[0031] Beneath the float chamber 12, the housing 10 provides an outletchamber 28. The lower end of the outlet chamber has a short pipe 30 thatin use is connected to an overflow pipe leading to the bath waste. Avalve hole 32 is formed in the dividing wall between the float chamber12 and the outlet chamber 28, and the valve hole 32 is normally closedby a valve member 34 mounted on a vertically moveable actuating rod 36.The valve member 34 and valve hole 32 together form an “overflow releasevalve” 38.

[0032] A valve block 40 is provided in, and to the rear of, the outletchamber 28. The valve block 40 provides: a cold-water passageway 42between a cold water inlet connector 44 (for connection to a cold watersupply) and a cold water outlet connector 46 (for connection to a coldtap for filling the bathtub); and a hot-water passageway 48 between ahot water inlet connector 50 (for connection to a hot water supply) anda hot water outlet connector 52 (for connection to a hot tap for fillingthe bathtub). A control-supply passageway 54 branches within the valveblock 40 from the cold-water passageway 42 to a valve hole 56. The valvehole 56 is normally closed by a valve member 58 also mounted on theactuating rod 36. The valve member 58 and valve hole 56 together form a“control valve” 59. Valve passageways 60,62 also branch within the valveblock 40 from the cold-water passageway 42 and hot-water passageway 48respectively. The cold-valve passageway 60 is downstream of thecontrol-supply passageway 54, and both valve passageways 60,62 are ofthe same diameter as the cold-water and hot-water passageways 42,48.Plungers 64,66 are slideably mounted in the cold-valve and hot-valvepassageways 60,62 respectively. The right-hand end (as viewed in FIGS. 7and 8) of each plunger 64,66 is hemispherical so that when the plungeris to the left the respective cold-water or hot-water passageway 42,48is open, and when the plunger is to the right the respective cold-wateror hot-water passageway 42,48 is closed (although complete sealing isunnecessary). Thus, each plunger 64,66 and its respective cold-water orhot-water passageway 42,48 form a respective “supply valve” 65,67. Theleft-hand ends of the plungers 64,66 are exposed to a control chamber 68formed in the valve block 40 above the control valve 59. The plungers64,66, and the valve passageways 60,62, are stepped in diameter so thatthe cross-sectional area of each plunger 64,66 exposed to the pressurein the cold-water or hot-water passageway 42,48 is less than thecross-sectional area of each plunger 64,66 exposed to the pressure inthe control chamber 68. So that the plungers 64,66 do not lock uphydraulically, each valve passageway 60,62 is vented at 70 to the outletchamber 28 adjacent the step in the passageway 60,62. Also, theactuating rod 36 passes through a hole 72 in the valve block 40 leadingto the control chamber 68 with a small clearance to provide a bleed fromthe control chamber 68 to the outlet chamber 28.

[0033] A compression spring 74 is mounted between the valve block 40 andthe underside of the overflow release valve member 34 so as urge theactuating rod 36 upwardly. However, the actuating rod 36 is normallyheld in a lower position (see FIGS. 3 and 4) by a detent mechanism 76 inthe float chamber 12. The detent mechanism 76 comprises a crank that ispivoted about a pin 78 extending across the float chamber 12. The crankhas a generally vertical arm 80 with a hooked finger 82 that can engagea shoulder or circlip 84 on the actuating rod 36, and a generallyhorizontal arm 86 that can be engaged by the float 14 when the floatrises to pivot the crank (as shown by phantom lines 87 in FIG. 4) andrelease the finger 82 from the shoulder 84, whereupon the actuating rod36 rises under the action of the spring 74. In order to return theactuating rod to its lower position, a resetting lever 88 is pivoted totrunnions 90 mounted behind the rosette 24. The left-hand end 92 (asseen in FIG. 3) of the resetting lever 88 projects through a centralhole in the rosette 24 and is manually operable. The right-hand end 94of the resetting lever 88 engages between a pair of shoulders orcirclips on the actuating rod 36.

[0034] The operation of the plumbing unit will now be describedcommencing with a first state, as shown in FIGS. 3 and 7, in which thefloat chamber 12 is empty, the actuating rod 36 is held in its lowerposition by the detent mechanism 76, the overflow release valve 38 andcontrol valve 59 are closed, and the supply valves 65,67 are open. Thebathtub taps can therefore be operated normally to fill the bathtub withcold and hot water flowing through the supply valves 65,67.

[0035] If the level of water in the bathtub should rise so that itspills through the rosette 24 into the float chamber 12, the level ofthe float 14 in the float chamber 12 will rise until it bears againstthe horizontal arm 86 of the detent mechanism 76, as shown in FIG. 4.Further spillage of water into the float chamber 12 will eventuallycause the detent mechanism 76 to trip as shown by the phantom lines 88,so that the actuating rod 36 moves upwardly under the action of thespring 74 to open the overflow release valve 38 and the control valve59, as shown in FIG. 5.

[0036] Once the overflow release valve 38 is open, the water in thefloat chamber 12 (and any further water that spills into the floatchamber 12) can drain to the outlet chamber 28 and thence to the bathwaste.

[0037] Also, once the control valve 59 opens, water from the cold supplycan pass though the control-supply passageway 54 to the control chamber68. Assuming that the pressure of the hot-water supply is less than orequal to the pressure of the cold-water supply, the pressure of thecold-water supply in the control chamber 68 will apply forces to theright on the left-hand ends of the plungers 64,66 that are greater thanthe forces applied to the left on the right-hand ends of the plungers64,66 by the pressures of the cold-water supply and hot-water supply,respectively, due to the stepping of the plungers 64,66 and passageways60,62. Accordingly, the plungers 64,66 move to the right to close thecold and hot supply valves 65,67 as shown in FIGS. 5 and 8, so thatfurther filling of the bathtub from the cold-water and/or hot-watersupplies is prevented or severely curtailed. It should be noted that ifthe cold and hot supply valves 65,67 do not close completely so that thebathtub continues to overflow slightly, the further overflow water canescape from the float chamber 12 through the open overflow release valve38 to the outlet chamber 28 and thence to the bath waste.

[0038] Furthermore, once the actuating rod 36 moves to its upperposition, the resetting lever 88 pivots so that its exposed end 92 movesto a lower position.

[0039] When the user of the bathtub returns to find that the bathtub isfull and is no longer being filled with cold or hot water, the user canclose the cold and hot taps and push the exposed end 92 of the resettinglever 88 upwards so that the actuating rod 36 again becomes held in itslower position by the detent mechanism 76, as shown in FIG. 3. (Toassist the detent mechanism 76 in clicking into place, a light spring(not shown) may be provided.) The control valve 59 therefore closes, andthe water in the control chamber 68 can bleed through the hole 72 to theoutlet chamber 28 so that the pressure in the control chamber 68 canreturn to atmospheric. The pressure of the water in the control chamber68 will therefore apply forces to the right on the plungers 64,66 thatare less than the forces applied to the left on the plungers 64,66 bythe pressures of the cold-water supply and hot-water supply.Accordingly, the plungers 64,66 move to the left to open the cold andhot supply valves 65,67 as shown in FIGS. 4 and 7, so that the bathtubcan be filled with water from the cold-water and hot-water supplies uponsubsequent opening of the cold and hot taps.

[0040] In the arrangements described above, conventional bath taps areprovided in addition to the supply valves 65,67. However, in the casewhen the supply valves 65,67 are manufactured to provide a sufficientlygood seal when closed, such conventional bath taps may be omitted. Inthat case, the plumbing unit would normally be in the state shown inFIG. 5 with both supply valves closed. To fill the bathtub, the wasteplug would be fitted to the bathtub, and the lever 88 would be moved tothe position shown in FIG. 2, so that the supply valves 65,67 would openand the bathtub would begin to fill. Once the bathtub began to overflow(FIG. 4), the plumbing unit would revert to the state shown in FIG. 5and the supply valves 65,67 would close. Of course, in order to emptythe bathtub, the waste plug would simply be removed. With thismodification, an adjustable thermostatic mixer may be provided to varythe proportions of hot and cold water so that the bath water is at adesired temperature. Assuming that the thermostatic mixer is leftadjusted to the desired temperature, it will therefore be appreciatedthat filling the bathtub with water of the desired temperature withoutany significant wastage of water merely entails fitting the waste plugto the waste outlet of the bathtub and pushing up the end 92 of thelever 88.

[0041] Many modifications and developments may be made to the embodimentof the invention described above. For example, FIG. 9 is a view similarto FIG. 3, but of a modified plumbing unit. The unit of FIG. 9 does nothave an overflow release valve. Instead, water can pass from the floatchamber 12 to the outlet chamber 28 by overflowing a weir 96 at a levelhigher than the water level in the float chamber 12 required to trip thedetent mechanism 76. Accordingly, even if the detent mechanism 76 failsto operate, overflow water can still pass from the float chamber 12 tothe outlet chamber 28.

[0042] The unit of FIG. 9 also has a modified control valve 59 formed bya pair of raised, spaced-apart seals 98,100 at the lower end of theactuating rod 36 slideable in a bore in the valve block 40. In theposition of the actuating rod 36 shown in FIG. 9, the flow of water fromthe control-supply passageway 54 to the control chamber 68 is blocked,but the control chamber 68 is vented via a bleed passageway 102 to theoutlet chamber 28. Once the detent mechanism 76 trips, the actuating rod36 is moved upwardly by a spring (not shown) so that the control valve59 connects the control-supply passageway 54 to the control chamber 68to close the supply valves 65,67, and so that the communication betweenthe control chamber 68 and the bleed passageway 102 is blocked.Accordingly, by comparison with the embodiment of FIGS. 1 to 8, theactuating rod 36 does not receive any net axial force from the watersupply that might interfere with the operation of the detent mechanism76. Furthermore, when the detent mechanism 76 has tripped, water cannotbleed from the control chamber 68 to the outlet chamber 28.

[0043] Referring now to FIGS. 10 and 11, a bathtub 104 is shown havingside walls 106, end walls 108 and a bottom wall 110 for containingwater. A “false” end wall 112 is also provided, spaced from one of theend walls 108 to form a cavity 114. Inside the cavity 114, a plumbingunit 116 similar to that described above is fitted to the bottom wall110 of the bathtub 104 with the hot and cold inlet connectors 44,50 andthe waste connector 30 protruding through sealed holes in the bottomwall 110. A thermostatic mixer 118 with an temperature adjustment knob120 is fitted on a platform at the top of the false wall 112 and isconnected to the hot and cold outlet connectors 46,52 of the plumbingunit 116. The thermostatic mixer 118 has an outlet spout 122 overhangingthe bathtub. Unlike the plumbing unit of FIGS. 1 to 9, in FIGS. 10 and11 the actuating rod 36 projects upwardly from the plumbing unit 116 andpasses through the body of the thermostatic mixer 118 to an operatingknob 124. Also, unlike the plumbing unit of FIGS. 1 to 9, in FIGS. 10and 11 the overflow rosette 24 is connected to the plumbing unit 116 bya flexible hose 126. As can be seen in FIG. 11, the overflow rosette ismounted in a vertical slot 128 in the false wall 112 for slidingmovement to adjust the height of the rosette 24, and therefore the levelat which the bathtub overflows, and therefore the level at which theplumbing unit 116 cuts off the water supplies. The rosette 24 is held inthe selected position along the slot 128 by any suitable means.

[0044]FIGS. 12 and 13 show a modification to the arrangement of FIGS. 10and 11. In FIGS. 12 and 13, the bathtub 104 does not have a false wall,and the rosette 24 is fitted in the end wall 108 of the bathtub at a farlower fixed level than is conventional. The flexible hose 126 has alarge amount of slack between the rosette 24 and the plumbing unit 116and passes through a block 130 that is a sliding fit on the hot and coldoutlet connectors 46,52. A large-pitched screw 132 depends from thehousing of the thermostatic mixer 118 and screw-threadedly engages theblock 130. A further knob 136 is provided on the housing of thethermostatic mixer 118 that can be rotated to turn the screw 132 andthus adjust the height of the block 130 and therefore the height of theloop in the hose 126. In order to prevent siphoning, a flexible venthose (not shown) branches from the hose 126 within the block 130 and hasits other open end fixed in a position underneath the thermostatic mixer118. Accordingly, although the height of the overflow rosette 24 isfixed, the “effective height” of the overflow outlet (i.e. the height ofthe top of the loop in the hose 126) is adjustable to adjust the heightto which the bathtub 104 fills before the plumbing unit 116 cuts off thewater supply.

[0045] The arrangement of FIGS. 12 and 13 may be modified to employother means for adjusting the height of the top of the loop in the hose126. Also, an indicator may be provided to indicate to the user theheight to which the system has been set.

[0046] The arrangements of FIGS. 10 to 13, and also of FIGS. 1 to 9insofar as the resetting lever 88 is concerned, may be modified toemploy electrically-powered or float-powered valves that are known perse, rather than the hydraulically-powered valves of FIGS. 1 to 9.

[0047] It should be noted that the embodiments of the invention havebeen described above purely by way of example and that many othermodifications and developments may be made thereto within the scope ofthe present invention.

1. An overflow system for a water receptacle (22) such as a bathtub,sink or washbasin for connection to a water supply, the system includingsensing means (14) for sensing an overflow condition of the receptacle,and a supply valve (65) responsive to the sensing means and arranged toclose the water supply, characterised in that the supply valve ishydraulically controllable via a control port (68) thereof, a controlvalve (59) is provided between the water supply and the control port,and the control valve is responsive to the sensing means so that uponsuch an overflow condition the control valve opens and the pressure ofthe water supply is applied to the control port of the supply valve toclose the supply valve.
 2. A system as claimed in claim 1, wherein thesupply valve comprises a plunger (64) movable between a closed positionin which a first end of the plunger closes the water supply and an openposition in which the first end of the plunger opens the water supply,the second end of the plunger being exposed to the pressure applied tothe control port.
 3. A system as claimed in claim 2, wherein thecross-sectional area of the first end of the plunger exposed to thepressure of the water supply is less than the cross-sectional area ofthe second end of the plunger exposed to the pressure applied to thecontrol port.
 4. A system as claimed in any preceding claim, for such awater receptacle connected to a second water supply, the system furtherincluding a second supply valve (67) arranged to close the second watersupply, the second supply valve being hydraulically controllable via acontrol port (68) thereof, the control valve also being provided betweenthe first-mentioned water supply and the control port of the secondsupply valve so that upon opening of the control valve the pressure ofthe first water supply is applied to the control port of the secondsupply valve to close the second supply valve.
 5. A system as claimed inany preceding claim for such a receptacle having an overflow outlet(20), further including: an actuating element (36) for operating thecontrol valve, the actuating element being held in a first positionbefore such an overflow condition and moving from the first position toa second position upon such an overflow condition; and amanually-operable resetting element (88) for moving the actuatingelement back from the second position to the first position, theresetting element projecting (at 92) through or being accessible throughthe overflow outlet.
 6. A system as claimed in claim 5, furthercomprising a detent element (76) for holding the actuating element inthe first position, and the sensing means comprising a float (14) forfloating on water that has escaped through the overflow outlet andarranged to release the detent element upon rising of the float.
 7. Anoverflow system for a water receptacle (22) such as a bathtub, sink orwashbasin having an overflow outlet (20) and being for connection to awater supply, the system including sensing means (14) for sensing anoverflow condition of the receptacle, and being changeable in responseto such an overflow condition from a first state in which the supply isopen and a second state in which the supply is closed, and the systemfurther including a manually-operable resetting element (88) forchanging the system back from the second state to the first state,characterised in that the resetting element projects (at 92) through oris accessible through the overflow outlet.
 8. An overflow system asclaimed in any preceding claim, wherein the effective height of theoverflow outlet relative to the receptacle is adjustable.
 9. An overflowsystem for a water receptacle (22) such as a bathtub, sink or washbasinhaving an overflow outlet (20) and for connection to a water supply, thesystem including sensing means (14) for sensing an overflow condition ofthe receptacle in which water flows into the overflow outlet, and meansfor closing the water supply in response to such an overflow condition,characterised in that the effective height of the overflow outletrelative to the receptacle is adjustable.
 10. A system as claimed inclaim 9, wherein the height of the entrance (24) into the overflowoutlet is adjustable.
 11. A system as claimed in claim 9, wherein theheight of an overflow passageway (126) leading from the entrance intothe overflow outlet is adjustable.
 12. A water receptacle (22), such asa bathtub, sink or washbasin, having an overflow system as claimed inany preceding claim.